@soix Like you, I'll use my ears to test, but I also want to try to understand some of the "why" behind what I'm hearing. My understanding is that for coax and ethernet applications, solid core copper is the best industrial option vs stranded copper or copper coated aluminum. E.g. solid core is best for power over ethernet applications like cameras or wifi access points, and solid copper products can also transfer over longer distances. It would make sense to me then that solid core products would benefit sensitive A/V components too. So if you're looking for affordable ethernet cable to test, you may be interested in this oxygen free, solid core copper ethernet cable I found on Amazon. I wired my whole house with it. Once I started buying enough to wire an entire house, it cost about twice as much as the stranded copper alternatives, but I didn't want to skimp out. Hit me up once you start testing ethernet cables. I'll join you.
Cat 8 Ethernet Cable 1.5ft Shielded, Indoor&Outdoor, Heavy Duty High Speed Direct Burial 26AWG Cat8 Network Wire, 40Gbps 2000Mhz SFTP Patch Cord, in Wall&Weatherproof RJ45 Cable for Router/Modem/Xbox https://a.co/d/4ZcnKcR